ZhangYang's Blog

Handlerbars.js模板引擎

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Handlerbars.js官网

http://handlebarsjs.com/

使用

HTML = structure + data

HTML = 结构 + 数据

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// 结构
<div class="entry">
  <h1>{{title}}</h1>
  <div class="body">
    {{body}}
  </div>
</div>
// 数据
data = {title: "My New Post", body: "This is my first post!"}
// 「编译」出 HTML
let html = Handlebars.compile(结构)(数据)
// 例子
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>柯里化</title>
  <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
</head>
<body>
  <script src="https://cdn.bootcss.com/handlebars.js/4.0.12/handlebars.min.js"></script>
  <script>
    let code = '<p>{{xxx}}</p>'
    let data = {xxx: 'zhangyang'}
    let html = Handlebars.compile(code)(data)
    console.log(html)
  </script>
</body>
</html>

柯里化

柯里化就是「减少参数」:如果你固定某些参数，你将得到接受余下参数的一个函数

Handlebars.compile(code)(data) 就用到了 curry

柯里化的形式

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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>柯里化的形式</title>
  <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
</head>
<body>
  <script src="https://cdn.bootcss.com/handlebars.js/4.0.12/handlebars.min.js"></script>
  <script>
    let code = '<p>{{xxx}}</p>'
    let 中间函数 = Handlebars.compile(code)
    let html = 中间函数({xxx: 'frank'})
    let html2 = 中间函数({xxx: 'jack'})
    console.log(html)
    console.log(html2)
  </script>
</body>
</html>
// 柯里化的实现
// 传3个参数
function calc(operator,number1,number2){
  switch(operator){
    case '+':
      return number1 + number2
    case '-':
      return number1 - number2
    case '*':
      return number1 * number2
    case '/':
      return number1 / number2;
  }
}
console.log(calc('+',1,2))
console.log(calc('+',10,20))
// 柯里化减少传2个参数
function calc(operator,number1,number2) {
  switch(operator){
    case '+':
      return number1 + number2;
    case '-':
      return number1 - number2;
    case '*':
      return number1 * number2;
    case '/':
      return number1 / number2;
  }
}
function add(number1,number2){
  return calc('+',number1,number2)
}
console.log(add(1,2))
console.log(add(10,20))

反柯里化

反柯里化就是增加参数

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// 反柯里化的实现
function fn(p1,p2){
  console.log(this)
  console.log(p1)
  console.log(p2)
}
function fn2(context,p1,p2){
  return fn.call(context,p1,p2)
}
fn2(1,2,3) // 1 2 3